This application is copending with U.S. patent application Ser. No. 125,642, filed Nov. 1, 1987, now U.S. Pat. No. 4,786,499 for "Lithium Electrochemical Cell Including Aprotic Solvent-Dialkyl Carbonate Solvent Mixture" and assigned to a common assignee. In that application, there is described and claimed a lithium electrochemical cell including lithium as the anode, non-stoichiometric (NS)-V.sub.6 O.sub.13 as the cathode, and a solution of a lithium salt in a mixed organic solvent of methyl formate and diethylcarbonate as the electrolyte.
Another lithium intercalating compound, to wit, Li.sub.x CoO.sub.2 (0&lt;x&lt;1) is particularly attractive for battery applications because of its inherently high energy content. However, the known Li.sub.x CoO.sub.2 cathode material/solvent combinations are susceptible to oxidation during charge and reduction during discharge that results in losses in cell capacity and cycle-life. In addition to oxidation and reduction of the electrolyte, both the cathode and anode are subject to reaction with the solvent and electrolyte. This can result in poor lithium cyclability and structural rearrangement of the active material which may limit rechargeability.